A new paper published in Environmental Research Letters examines 8 datasets of temperature & precipitation observations in China over the past 105 years and finds significant unexplained differences between datasets, concluding,

"Because observations coming from different datasets do have differences, which one we can believe among the various so-called ‘observed climate datasets’? Indeed, we have no ability to know the ‘truth value’"

Indeed, two of the Chinese datasets in the paper show there was essentially no warming in China from 1950-2005.

Furthermore, the paper notes that because we don't know which temperature datasets are correct [if any], climate models based upon flawed temperature data will result in erroneous "tuning" of climate models and therefore biased projections i.e. GIGO]. Excerpt from the conclusion:

All of these results bring about a new challenge in the ﬁeld of climate change. So-called ‘observed climate datasets’ play important roles in driving hydrologic models, evaluating global circulation models (GCMs) and regional climate models (RCM). Because observations coming from different datasets do have differences, which one we can believe among the various so-called ‘observed climate datasets’? Indeed, we have no ability to know the ‘truth value’; what we need to do is reduce the disagreement among the ‘observed datasets’ and depress their uncertainty.

As lamented in Climategate emails by Phil Jones to James Hansen, if the Chinese stopped their commendable practice of moving thermometers away from contamination by the Urban Heat Island [UHI] effect and instead taken temperature readings contaminated by airport jet exhaust [as the rest of the world did], the Chinese temperature data would have shown more artificial warming. One can't deny that temperature data contradictions, contamination, errors and tampering are indeed a worldwide climate phenomenon.

What a wonderful, refreshing article. The "Warmists" just keep at it, and I get so tired of the fear mongering. We are so blessed to live in this incredibly interesting world, and these AGW people are totally determined to destroy the very life they enjoy themselves. Strange, isn't it? For myself, I love fossil fuels!! I love carbon dioxide as much as plants do!! More CO2, more oxygen for me and other animal life! Three cheers for this wonderful symbiosis.